KIDNEY STONES.

Kidney Stones may get trapped in the urinary tract and cause severe pain.

What are the symptoms of kidney stones?

Renal Colic is the term used to describe pain caused by kidney stones. Kidney stones can block the ureter (the tube from each kidney to the bladder). The blockage causes spasm of the muscles of the ureter, and this is called “renal colic.” (There are other causes of renal colic apart from stones but most doctors use the term renal colic to describe pain caused by stones).

The pain is typically comes on suddenly and is felt as pain in the loin (the flank – underneath the ribs) that comes in waves. However, the precise location of the pain depends on the level at which the stone obstructs the ureter. The stone can obstruct the ureter where it connects to the kidney, or the middle of the ureter (its most narrow part) or at the bottom of the ureter where it connects with the bladder (the most common location). So pain may be felt higher up in the loin, in the middle of the loin, or lower down towards the pelvis if the obstruction is lower.

How is the diagnosis confirmed?

The diagnosis is confirmed by testing the urine for blood and then some sort of imaging test. The imaging test could be a plain xray, ultrasound (both would often be combined), and/or a CT scan. The CT scan is the most sensitive test but involves some radiation. The investigations are arranged either by The GP or at the emergency department. Lower radiation scanners are also available.

Stones most often pass spontaneously – good news as you wouldn’t need any intervention! The chances of stones passing on their own are highest for stones found at the bottom of the ureter, and for smaller stones. 85% of stones pass spontaneously if enough time is given. Almost all stones less than 5mm will pass on their own. Those more than 10mm may need to be removed. Intervention will depend mainly on time (stones not passed within 4-6 weeks on their own are unlikely to do so) and pain.

What is the treatment?

Let’s look at treatment by the size of the stone.

  • Stones <5mm are likely to pass on their own.
  • Stones 5-10mm could be ‘helped along’ with medication such as nifedipine or an ‘alpha blocker.’
  • Stone >10mm or stones that are ‘stuck’ may need surgical treatment.

Taking a medication to expel moderate size stones is a very attractive idea. Unfortunately the medication is not that effective. Having said that, most doctors do suggest a trial of ‘medical therapy’ at least to reduce the pain levels.

Surgical treatments include:

  • Shockwave therapy (lithotripsy)
  • Grabbing the stone from the ureter (uteroscopy)

Lithotripsy therapy started over 30 years ago with powerful shock waves that are focused on the stone. Treatment may need to be repeated, and treatment of stones larger than 10mm is not as successful as treatment of smaller stones.

Ureteroscopy allows crystal clear images of the stones within the ureter. The procedure requires a general anaesthetic. The stones can be removed using a specially designed basket, and then sent off for analysis. Another option is simply to reduced the stone to dust using laser devices.

A stent is often left in place after ureteroscopy, and this will need removing at a later date often without anaesthetic.

WRITTEN BY: Dr Richard Beatty
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